Nano-Resolved Current-Induced Insulator-Metal Transition in the Mott Insulator Ca2RuO4
Nano-Resolved Current-Induced Insulator-Metal Transition in the Mott Insulator Ca2RuO4
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DOI：
10.1103/physrevx.9.011032
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发表时间：
2019-02
影响因子：
12.5
通讯作者：
Jiawei Zhang;A. Mcleod;Q. Han;Xinzhong Chen;H. Bechtel;Z. Yao;S. G. Gilbert Corder;Thomas Ciavatti;T. Tao;M. Aronson;G. L. Carr;Michael C. Martin;C. Sow;S. Yonezawa;F. Nakamura;I. Terasaki;D. Basov;A. Millis;Y. Maeno;Mengkun Liu
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文献类型：
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作者：
Jiawei Zhang;A. Mcleod;Q. Han;Xinzhong Chen;H. Bechtel;Z. Yao;S. G. Gilbert Corder;Thomas Ciavatti;T. Tao;M. Aronson;G. L. Carr;Michael C. Martin;C. Sow;S. Yonezawa;F. Nakamura;I. Terasaki;D. Basov;A. Millis;Y. Maeno;Mengkun Liu
作者：张，J；麦克劳德,;汉族,问;陈,X;贝克特尔,哈;姚,Z;吉尔伯特·科德，SN；Ciavatti T;道,TH;Aronson, M;卡尔,GL;马丁,MC;播种,C;Yonezawa年代;中村,F;寺崎,我;Basov DN;米尔斯,AJ;Maeno Y;摘要：©2019作者。由美国物理学会出版。由美国物理学会根据»https://creativecommons.org/licenses/by/4.0/»知识共享署名4.0国际许可条款发布。这项工作的进一步分发必须保持作者的归属和已发表文章的标题，期刊引用和DOI。莫特绝缘体Ca2RuO4是最近备受关注的主题，因为有报道称，在外加电场或电流的驱动下，出现了非平衡稳态。在本文中，我们对Ca2RuO4块状单晶在稳定电流条件下进行了红外纳米成像和光学显微镜测量，以深入了解电流驱动的绝缘子到金属的转变。我们观察到电流诱导金属相的宏观生长，金属相和绝缘体相的成核区域由电流的极性决定。在相前观察到金属-绝缘体-金属的微条纹模式。微条纹的方向与晶体轴紧密相连，这意味着电子跃迁与晶格自由度之间存在很强的耦合。理论模型进一步说明了电流密度的重要性，并证实了在大块金属相的相前存在亚微米厚的表面金属层。我们的工作证实了电诱导金属相是非丝状的，并且不是由焦耳加热驱动的，揭示了在功能相关氧化物中发生的电诱导绝缘体-金属转变的显着新特征。
Author(s): Zhang, J; McLeod, AS; Han, Q; Chen, X; Bechtel, HA; Yao, Z; Gilbert Corder, SN; Ciavatti, T; Tao, TH; Aronson, M; Carr, GL; Martin, MC; Sow, C; Yonezawa, S; Nakamura, F; Terasaki, I; Basov, DN; Millis, AJ; Maeno, Y; Liu, M | Abstract: © 2019 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. The Mott insulator Ca2RuO4 is the subject of much recent attention following reports of emergent nonequilibrium steady states driven by applied electric fields or currents. In this paper, we carry out infrared nano-imaging and optical-microscopy measurements on bulk single crystal Ca2RuO4 under conditions of steady current flow to obtain insight into the current-driven insulator-to-metal transition. We observe macroscopic growth of the current-induced metallic phase, with nucleation regions for metal and insulator phases determined by the polarity of the current flow. A remarkable metal-insulator-metal microstripe pattern is observed at the phase front separating metal and insulator phases. The microstripes have orientations tied uniquely to the crystallographic axes, implying a strong coupling of the electronic transition to lattice degrees of freedom. Theoretical modeling further illustrates the importance of the current density and confirms a submicron-thick surface metallic layer at the phase front of the bulk metallic phase. Our work confirms that the electrically induced metallic phase is nonfilamentary and is not driven by Joule heating, revealing remarkable new characteristics of electrically induced insulator-metal transitions occurring in functional correlated oxides.